Method and system for modem protocol discrimination

ABSTRACT

The invention provides a method of selecting a modem carrier type for data transmission over a wireless communication system. An incoming call is received from a mobile vehicle and then an initial carrier tone is sent to a mobile vehicle in response to the incoming call. A modem response signal is received from a vehicle modem in response to the initial carrier tone. The modem response signal is determined to be either an analog modem response signal or a digital modem response signal, and then the call is connected to either the analog modem or digital modem based on the modem response signal determination.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/061,406 filed on Jan. 31, 2002 now U.S. Pat. No. 7,224,998, which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

This invention relates generally to data transmission over a wirelesscommunication system. More specifically, the invention relates to amethod and system for detecting and determining a modem type.

BACKGROUND

Wireless modems may send and receive data streams or data packetsthrough an air interface. Wireless modems may be an analog type, such asa Bell 103 modem operating in accordance with the Bell 103 standard orother standards suitable for data communications over analog cellularvoice channels. A wireless modem may be a digital type, operating inaccordance with emerging standards suitable for data communications overdigital cellular or PCS voice channels. Data transmissions may occurover wireless links by modulating a radio center frequency or band offrequencies in a prescribed fashion using one of a variety of modulationand encoding techniques, such as frequency modulation, frequency shiftkeying, phase shift modulation or frequency spreading methods, toaccurately transmit and receive data through the airwaves. Once a radiocommunication channel is established, an incoming signal from a wirelessmodem may be received, amplified, demodulated and then reconstructedinto data packets. An outgoing data packet may be formattedappropriately, and an outgoing transmission sent.

Transmissions of data between modems may occur over a wireless link, awired link, a fiber link, or a combination thereof. An analog modem mayoperate, for example, using an analog mobile phone system such as theadvanced mobile phone system (AMPS) over a band of frequencies nominallyat 800 MHz. A digital modem may operate, for example, over a digitalcellular or digital PCS (personal communication services) band nominallyat 800 MHz, 900 MHz or 1900 MHz. An analog modem or a digital modem mayoperate, for example, over any suitable band of frequencies.Transmission of data over a digital wireless link using an analog modemmay not work adequately due to circuitry and encoding algorithms in themobile phone network that are optimized for voice transmissions. Datarates achievable with a digital wireless modem may be appreciably higherand more desirable than that of an analog wireless modem. Transmissionof data from a digital or analog modem may occur, in part, overland-based communication lines, which may be part of a public switchedtelephone system.

The protocol required to transmit data streams or data packets betweenmodems requires each modem to be operating in either an analog ordigital mode. For a large number of phone calls coming into a callcenter, for example, it may be unknown whether an incoming data call isfrom an analog modem or a digital modem. Thus, the receiving end isrequired to determine whether an analog or a digital modem is initiatingcommunication, and to set up the call accordingly.

A call may be initiated from a mobile vehicle, for example, to requestand receive from a call center a variety of services, such as navigationinstructions, directory assistance, road condition information, roadsideassistance, Internet access, short messages, text messages, audiostreams or video information. Many mobile vehicles are currentlyequipped with analog modems and switches that allow a sequence of dataand voice sessions to occur. Newer vehicles may be equipped with digitalmodems, which offer higher speed and higher reliability in datatransmissions. A call center may need, for example, to make adetermination whether an incoming data call is being originated from avehicle with an analog or a digital modem, and furthermore, to establisha connection with the mobile vehicle using the correct modem type suchthat the correct protocols may be used for accurate and reliable datatransmission.

It is an object of this invention, therefore, to provide a method formodem protocol discrimination, and to overcome the deficiencies andobstacles described above.

SUMMARY OF THE INVENTION

One aspect of the invention provides a method of selecting a modemcarrier type for data transmission over a wireless communication system.An incoming call may be received from a mobile vehicle. An initialcarrier tone may be sent to a mobile vehicle in response to the incomingcall. A modem response signal may be received from a vehicle modem inresponse to the initial carrier tone. The modem response signal may bedetermined to be either an analog modem response signal or a digitalmodem response signal, and then the call may be connected to either ananalog modem or digital modem based on the modem response signaldetermination.

The initial carrier tone may be a nominally 2225 Hz tone. The modemresponse signal may be a nominally 1270 Hz tone indicating an analogvehicle modem. The modem response signal may be a connect request signalindicating a digital vehicle modem.

A call routing number associated with the incoming call may be comparedto a database of call routing numbers; and the initial carrier tone maybe sent when the call routing number does not match one of the callrouting numbers in the database.

The initial carrier tone may be disabled upon detecting a modem responsesignal. The incoming call may be terminated when no modem responsesignal is received in response to the initial carrier tone.

Another aspect of the invention provides a wireless modem system forselecting a modem carrier type. The system may include a means forreceiving an incoming call from a mobile vehicle. The system may includea means for sending an initial carrier tone to the mobile vehicle inresponse to the incoming call, and a means for receiving a modemresponse signal from a vehicle modem in response to the initial carriertone. The system may include a means for determining whether the modemresponse signal is an analog modem response signal or a digital modemresponse signal, and a means for connecting the call to one of an analogmodem or a digital modem based on the modem response signaldetermination.

The system may further include a means for comparing a call routingnumber associated with the incoming call to a database of call routingnumbers; and a means for sending the initial carrier tone when the callrouting number does not match with one of the call routing numbers inthe database.

The system may further include a means for disabling the initial carriertone upon detecting a modem response signal and a means for terminatingthe incoming call when no modem response signal is received in responseto the initial carrier tone.

Another aspect of the present invention provides a computer usablemedium including a program for selecting a modem carrier type.

The program may include computer program code for receiving an incomingcall from a mobile vehicle. The program may include computer programcode for sending an initial carrier tone to the mobile vehicle inresponse to the incoming call. The program may include computer programcode for receiving a modem response signal from a vehicle modem inresponse to the initial carrier tone. The program may include computerprogram code for determining whether the modem response signal is ananalog modem response signal or a digital modem response signal. Theprogram may include computer program code for connecting the call to ananalog modem or a digital modem based on the modem response signaldetermination.

The program may include program code wherein the initial carrier tone isa nominally 2225 Hz tone. The program may include program code whereinthe modem response signal is a nominally 1270 Hz tone indicating ananalog vehicle modem. The program may include program code wherein themodem response signal is a connect request signal indicating a digitalvehicle modem.

The computer usable medium may further include computer program code forcomparing a call routing number associated with the incoming call to adatabase of call routing numbers; and computer program code for sendingthe initial carrier tone when the call routing number does not matchwith one of the call routing numbers in the database.

The program may further include computer program code for disabling theinitial carrier tone upon detecting a modem response signal. The programmay include program code for terminating the incoming call when no modemresponse signal is received in response to the initial carrier tone.

The aforementioned, and other features and advantages of the inventionwill become further apparent from the following detailed description ofthe presently preferred embodiments, read in conjunction with theaccompanying drawings. The detailed description and drawings are merelyillustrative of the invention rather than limiting, the scope of theinvention being defined by the appended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of embodiments of the present disclosure willbecome apparent by reference to the following detailed description anddrawings, in which like reference numerals correspond to similar, thoughnot necessarily identical, components. For the sake of brevity,reference numerals or features having a previously described functionmay not necessarily be described in connection with other drawings inwhich they appear.

FIG. 1 is an illustration of one embodiment of a system for selecting amodem carrier type for data transmission over a wireless communicationsystem in accordance with the current invention;

FIG. 2 is a block diagram of one embodiment of a system for selecting amodem carrier type in accordance with the current invention; and

FIG. 3 is a flow diagram of one embodiment of a method for selecting amodem carrier type in accordance with the current invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows an illustration of one embodiment of a system for selectinga modem carrier type for data transmission over a wireless communicationsystem, in accordance with the present invention at 100.

Wireless modem protocol discrimination system 100 may include one ormore mobile communication devices 110; one or more carrier systems 120;one or more wireless networks 130; one or more land networks 140; andone or more communication nodes. A communication node may contain one ormore data and voice switches 150; one or more communication node modems160; one or more advisors 170; one or more vehicle communicationservices managers 180, and one or more bus systems 190. A communicationnode may be a call center where many calls may be received and servicedat a time. Alternatively, a communication node may be a modem card in awireless modem bank, or a computer with a modem integrated circuit, or adigital signal processor with modem capability, or a stand-alone modem,or a portable wireless communication device, or another mobilecommunication device 110.

Mobile communication device 110 may be a portable wireless communicationdevice, or a mobile vehicle equipped with suitable hardware and softwarefor transmitting and receiving voice and data communications. Mobilecommunication device 110 may contain a wireless modem for transmittingand receiving data. The wireless modem may be an analog modem or adigital modem. The wireless modem may reside in a digital signalprocessor located in the wireless communication device, a hostprocessor, a cellular phone, or a mobile phone residing in a mobilevehicle. Mobile communication device 110 may be carried by a user ormounted in a mobile vehicle. Mobile communication device 110 may containsuitable hardware and software for transmitting and receiving voice anddata communications. Mobile communication device 110 may send to andreceive radio transmissions from carrier system 120.

Carrier system 120 may be a wireless communications carrier. Carriersystem 120 may be, for example, a mobile telephone system. The mobiletelephone system may be an analog mobile telephone system operating overa prescribed band nominally at 800 MHz. The mobile telephone system maybe a digital mobile telephone system operating over a prescribed bandnominally at 800 MHz, 900 MHz, 1900 MHz, or any suitable band capable ofcarrying mobile communications. Carrier system 120 may transmit to andreceive signals from mobile communication device 110. Carrier system 120may transmit to and receive signals from a second mobile communicationdevice 110. Carrier system 120 may be connected with wireless network130.

Wireless network 130 may comprise a mobile telephone switching office.Wireless network 130 may comprise services from one or more wirelesscommunications companies. Wireless network 130 may be any systemconnecting carrier system 120 to a second mobile communication device110. Wireless network 130 may be any system connecting carrier system120 to land network 140.

Land network 140 may be a public switched telephone network. Landnetwork 140 may be comprised of a wired network, an optical network, afiber network, another wireless network, or any combination thereof.Land network 140 may connect wireless network 130 with a second carriersystem 120. Land network 140 may connect wireless network 130 to acommunication node.

The communication node may contain a switch 150. Switch 150 may beconnected to the land network 140, and may receive a modem carrier froman analog modem or from a digital modem. Switch 150 may transmit voiceor data transmission from the communication node. Switch 150 may alsoreceive voice or data transmissions from mobile vehicle 110 throughcarrier system 120, wireless network 130 and land network 140. Switch150 may receive or send data transmissions with communication node modemunit 160, or receive or send voice transmissions with advisor 170.

Communication node modem unit 160 may send data to or receive data fromswitch 150. Communication node modem unit 160 may be an analog modem, adigital modem, or include both an analog modem and a digital modem.Communication node modem unit 160 may include the ability to detect thetype of modem protocol of a received modem signal, and to establishconnectivity in accordance with the modem protocol. Communication nodemodem unit 160 may include the ability to send a carrier tone uponreceiving an incoming call, and to determine the modem type in responseto a received modem signal. Communication node modem unit 160 mayinclude the ability to determine whether the modem response signal isfrom an analog modem or from a digital modem. A modem may be, forexample, any suitable hardware and software operating in accordance withstandards Bell 103, Bell 212A, V.21, V.22, V.23, V.29, V.32, V.32bis,V.34, V.90, V.92 or any other modem standard. A wireless analog modemmay be, for example, any suitable hardware and software operating inaccordance with analog wireless communication standards. A wirelessdigital modem may be, for example, any suitable hardware and softwareoperating in accordance with digital wireless communication standards.Communication node modem unit 160 may be a modem card. Multiple modemcards may be located, for example, in a modem bank at a call center.Communication node modem unit 160 may transfer data to or from advisor170, vehicle communication services manager 180, or any other deviceconnected to bus system 190. Communication node modem unit 160 may beable to distinguish between an analog modem and a digital modem used indata transmissions from mobile vehicle 110, and operate accordingly.Communication node modem unit 160 may be a located in a second mobilecommunication device 110.

Advisor 170 may be a real advisor or a virtual advisor. A real advisormay be a human being in verbal communication with mobile communicationdevice 110. A virtual advisor may be a synthesized voice interfaceresponding to requests from mobile communication device 110. Advisor 170may provide services to mobile communication device 110. Servicesprovided by advisor 170 may include navigation assistance, directoryassistance, roadside assistance, business or residential assistance,information assistance, and emergency assistance. Advisor 170 maycommunicate with mobile communication device 110 using voice or datatransmissions. Advisor 170 may communicate with vehicle communicationservices manager 180 or any other device connected to bus system 190. Incases where no data transmissions occur, advisor 170 may be connected toan incoming call through switch 150.

Vehicle communication services manager 180 may be connected to switch150, modem 160, and advisor 170 through bus system 190. Vehiclecommunication services manager 180 may determine whether voice or datatransmissions are to occur with mobile communication device 110. Vehiclecommunication services manager 180 may provide instructions to switch150 whether a communication segment is a voice segment or a datasegment. Vehicle communication services manager 180 may provideinstructions to modem 160 regarding timing, protocols and signalmanagement. Signal management may include, for example, a determinationon whether the data that is being sent or received from mobile carrier110 should be set to an analog protocol or a digital protocol, orwhether an incoming call should be transferred to advisor 170. Signalmanagement may also include establishing connectivity and terminatingcalls.

FIG. 2 shows a block diagram of one embodiment of a system for selectinga modem carrier type in accordance with the present invention at 200.

Modem carrier type selection system 200 may be comprised of one or moremodem units 210. Modem unit 210 may contain a connectivity module 220,one or more digital modems 230, and one or more analog modems 240. Modemcarrier type selection system 200 may comprise transport layer module250, application programming interface (API) 260, and vehiclecommunication services module 270.

An inbound call may be connected to modem unit 210. Modem unit 210 maybe a printed circuit board with suitable electronic circuitry andsoftware for determining the modem carrier type of the incoming call andconnecting the call to either digital modem 230 or analog modem 240.Modem unit 210 may be a digital signal processor with the ability todetermine the modem carrier type of the incoming call. Modem unit 210may be a digital signal processor with the ability to determine themodem carrier type as well as provide the functions and signals of adigital modem and an analog modem. Modem unit 210 may comprise, forexample, a single chip integrated circuit encompassing connectivitymodule 220, digital modem 230 and analog modem 240.

Connectivity module 220 may contain suitable hardware and software forgenerating and sending an initial carrier tone in response to receivingan incoming call from a mobile vehicle or from a wireless modem notlocated in a mobile vehicle. Connectivity module 220 may containsuitable hardware and software for determining whether a modem responsesignal from the mobile vehicle is from an analog modem or a digitalmodem, and connecting the call to either digital modem 230 or analogmodem 240 in modem unit 210 based on the determination.

Digital modem 230 may receive data transmissions from an appropriatelyconnected inbound call. Digital modem 230 may send data transmissions byan appropriately connected outbound call, for example, to a digitalmodem in the mobile vehicle. Digital modem 230 may send and receive datatransmissions on a physical layer in correspondence with layer one ofthe OSI (open-systems interconnection) network model. Digital modem 230may send and receive physical layer data with transport layer module250.

Analog modem 240 may receive data transmissions from an appropriatelyconnected inbound call. Analog modem 240 may send data transmissions byan appropriately connected outbound call, for example, to an analogmodem in the mobile vehicle. Analog modem 240 may send and receive datatransmissions on a physical layer in correspondence with layer one ofthe OSI network model. Analog modem 240 may send and receive data withapplication programming interface 260.

Transport layer module 250 may contain suitable hardware and software tochange physical layer data from digital modem 230 to transport layerfour of the OSI network model. Transport layer module 250 may transferdata, for example, in data packets or blocks of data to applicationprogramming interface 260.

Application programming interface 260 may receive blocks of data or datapackets from digital modem 230 via transport layer module 250.Application programming interface 260 may send blocks of data or datapackets to digital modem 230 via transport layer module 250. Applicationprogramming interface 260 may send or receive streams of data, blocks ofdata or data packets with analog modem 240. Application programminginterface 260 may send control signals to digital modem 230 or to analogmodem 240 for the coordination of data flow and timing. Control signalsgenerated by application programming interface 260 may include, forexample, the sending of an initial carrier tone or the disabling of theinitial carrier tone when a modem response signal is received. If nomodem response signal is received in response to the initial carriertone, application programming interface 260 may connect, for example,the call to advisor 170 or terminate the incoming call. Applicationprogramming interface 260 may send data to or receive data from vehiclecommunication services module 270.

Vehicle communication services module 270 may provide a variety ofservices to mobile communication device 110. Mobile communication device110 may be mounted, for example, in a mobile vehicle. The user of themobile vehicle may request, for example, various services to be providedsuch as navigation instructions, directory assistance, road conditioninformation, roadside assistance, Internet access, short messages, textmessages, audio streams or video information. Vehicle communicationservices module 270 may acquire and manage the information requested bythe mobile vehicle. Vehicle communication services module 270 mayaccess, for example, one or more databases, or connect with otherservice and information modules to provide the desired information andservices.

FIG. 3 shows a flow diagram of one embodiment of a method for selectinga modem carrier type in accordance with the present invention at 300.Modem carrier type selection method 300 comprises a series of steps todetermine the protocol type and to provide connectivity to a suitablemodem.

An incoming call may be received (Block 305). The incoming call may beinitiated, for example, by a user in a mobile vehicle desiring servicessuch as roadside assistance, emergency services, or any of a number ofinformation and communication services. The incoming call may bereceived, for example, by a call center where large numbers of incomingcalls from various sources may be received. Upon reception of theincoming call, a comparison may be made of a call routing numberassociated with the incoming call to call routing numbers in a database.The call routing number associated with the incoming call may be thedialed number of the call center. The call routing number associatedwith the incoming call may be the phone number associated with themobile vehicle. The call routing number may be obtained, for example, byuse of an inbound dialed number information service (DNIS). The callrouting number may be obtained, for example, from an automatic numberidentification (ANI) service, such as caller ID. The database of callrouting numbers may contain information on whether the modem associatedwith the incoming call is an analog modem or a digital modem, and thenconnect the call to an analog modem or a digital modem accordingly.

If the comparison of the call routing number associated with theincoming call to a database of call routing numbers does not result in amatch, or if no call routing number is available, a carrier tone may begenerated (Block 310). The carrier tone may be, for example, a signal ata frequency of 2225 Hz. The carrier tone may be sent, for example, tothe mobile vehicle. A modem located at the mobile vehicle may recognizethe tone and send a modem response signal. If the modem in the mobilevehicle is an analog modem, the modem may respond with a 1270 Hz tone,for example, in accordance with Bell 103 standards. If the modem in themobile vehicle is a digital modem, the modem may respond to the carriertone, for example, with a connect request signal. Upon detecting a modemresponse signal, the initial carrier tone may be disabled.

A modem response signal may be received (Block 315). If no modemresponse signal is received, the incoming call may be terminated, forexample, after a specified number of seconds (Block 320).

If a modem response signal is received (Block 315), a determination maybe made as to whether the response is being received from an analogmodem or a digital modem. If the response corresponds to a digitalmodem, the carrier tone may be dropped and the call may be connected,for example, to a digital modem at the call center, (Block 330). Datamay then be transferred (Block 335), and the data transfer sessionterminated when data transfers are completed, (Block 340). Additionalvoice sessions and data sessions may follow, until the call is finallyterminated.

If a modem response signal is received indicating an analog modem, thecall may be connected to an analog modem at the call center, forexample, (Block 345). Data may then be transferred (Block 350). The datatransfer session may be terminated when data transfers are complete,(Block 355), or additional voice sessions and data sessions may followuntil the call is finally terminated.

While the embodiments of the invention disclosed herein are presentlyconsidered to be preferred, various changes and modifications can bemade without departing from the spirit and scope of the invention. Thescope of the invention is indicated in the appended claims, and allchanges that come within the meaning and range of equivalents areintended to be embraced therein.

1. A method of selecting a modem carrier type for data transmission overa wireless communication system, comprising: receiving an incoming callfrom a mobile vehicle; prior to sending an initial carrier tone,obtaining a call routing number associated with the incoming call via aninbound dialed number information service or an automatic numberidentification service; sending the initial carrier tone to the mobilevehicle in response to the incoming call and in response to i)determining that the call routing number is not available or ii)determining that the call routing number does not correspond with a callrouting number in a database of call routing numbers; receiving a modemresponse signal from a vehicle modem in response to the initial carriertone; determining whether the modem response signal is one of an analogmodem response signal or a digital modem response signal; and connectingthe call to one of an analog modem or a digital modem based on the modemresponse signal determination.
 2. The method of claim 1 wherein theinitial carrier tone is a nominally 2225 Hz tone.
 3. The method of claim1 wherein the modem response signal is the analog modem response signalincluding a nominally 1270 Hz tone indicating an analog vehicle modem.4. The method of claim 1 wherein the modem response signal is thedigital modem response signal including a connect request signalindicating a digital vehicle modem.
 5. The method of claim 1, furthercomprising disabling the initial carrier tone upon receiving the modemresponse signal.
 6. The method as defined in claim 5 wherein the modemresponse signal is the digital modem response signal including a connectrequest signal.
 7. A wireless modem system for selecting a modem carriertype, comprising: means for receiving an incoming call from a mobilevehicle; means for obtaining a call routing number associated with theincoming call via an inbound dialed number information service or anautomatic number identification service; means for sending an initialcarrier tone to the mobile vehicle in response to the incoming call,wherein the means for sending the initial carrier tone performs inresponse to i) determining that the call routing number is not availableor ii) determining that the call routing number does not correspond witha call routing number in a database of call routing numbers; means forreceiving a modem response signal from a vehicle modem in response tothe initial carrier tone; means for determining whether the modemresponse signal is one of an analog modem response signal or a digitalmodem response signal; and means for connecting the call to one of ananalog modem or a digital modem based on the modem response signaldetermination.
 8. The system of claim 7, further comprising means fordisabling the initial carrier tone upon receiving the modem responsesignal.
 9. The computer usable medium of claim 7 wherein the initialcarrier tone is a nominally 2225 Hz tone.
 10. The computer usable mediumof claim 7 wherein the modem response signal is the analog modemresponse signal including a nominally 1270 Hz tone indicating an analogvehicle modem.
 11. The computer usable medium of claim 7 wherein themodem response signal is the digital modem response signal including aconnect request signal indicating a digital vehicle modem.
 12. Acomputer usable medium including a program for selecting a modem carriertype, comprising: computer program code for receiving an incoming callfrom a mobile vehicle; computer program code for obtaining a callrouting number associated with the incoming call via an inbound dialednumber information service or an automatic number identificationservice, computer program code for sending an initial carrier tone tothe mobile vehicle in response to the incoming call and in response toi) determining that the call routing number is not available or ii)determining that the call routing number does not correspond with a callrouting number in a database of call routing numbers; computer programcode for receiving a modem response signal from a vehicle modem inresponse to the initial carrier tone; computer program code fordetermining whether the modem response signal is one of an analog modemresponse signal or a digital modem response signal; and computer programcode for connecting the call to one of an analog modem or a digitalmodem based on the modem response signal determination.
 13. The computerusable medium of claim 12, further comprising computer program code fordisabling the initial carrier tone upon receiving the modem responsesignal.